Pseudin Explained

Pseudin is a peptide derived from Pseudis paradoxa.[1] Pseudins have some antimicrobial function.[2] [3]

There are several different forms:

Pseudin-2

Pseudin-2 is the most abundant version of the pseudins found on the skin of the paradoxical frog.[8] The primary sequence reads as GLNALKKVFQGIHEAIKLINNHVQ. Its secondary/tertiary structure consists of one cationic amphipathic α-helix.[9]

Antibacterial activity

Pseudin-2 was shown to have potent antibacterial activity, but a lower cytotoxicity. The cytotoxicity of a peptide can be measured by its effect on human erythrocytes. It takes a lower concentration of Pseudin-2 to kill bacteria or fungi such as E. coli, S. aureus, and C. albicans than to kill human erythrocytes. It is hypothesized that Pseudin-2 binding to the cell membrane of the bacteria results in a conformational change in which the peptide forms an α-helical shape, which allows it to perform cell lysis by inserting itself in the hydrophobic portion of the membrane. This mechanism is applicable to similar amphipathic α-helical peptides created by many frog species, although most of these peptides aren't very potent against bacteria.[10] By increasing the cationicity and amphipathic nature of the molecule, it is possible to create analogues of Pseudin-2 that are even more selective towards bacteria. This is done by substituting leucine residues with lysine residues and glycine residues with proline residues, which results in two shorter α-helices (linked by the substituted proline) that are more attuned to penetrating bacterial cell membranes.

See also

Notes and References

  1. Web site: InterPro: IPR013156 Pseudin antimicrobial peptide . 2008-03-02 .
  2. Book: senior reporters . G.C. Barrett . J.S. Davies. . Amino acids, peptides and proteins . limited . Royal Society of Chemistry . Cambridge, Eng . 2004 . 72 . 0-85404-242-3 .
  3. Rinaldi AC . Antimicrobial peptides from amphibian skin: an expanding scenario . Curr Opin Chem Biol . 6 . 6 . 799–804 . 2002 . 12470734 . 10.1016/S1367-5931(02)00401-5.
  4. Web site: Pseudin-1 - Pseudis paradoxa (Paradoxical frog) . 2008-03-02 .
  5. Abdel-Wahab YH, Power GJ, Ng MT, Flatt PR, Conlon JM . Insulin-releasing properties of the frog skin peptide pseudin-2 and its [Lys(18)]-substituted analogue . Biol. Chem. . 389 . 2 . 143–8 . 2008 . 18163889 . 10.1515/BC.2008.018 . 5411214 .
  6. News: Jungle frog's anti-infection agent may help millions of diabetics - Times Online . 2008-03-02 . The Times . London . David . Rose . 2008-03-03.
  7. Web site: Pseudin-4 - Pseudis paradoxa (Paradoxical frog) . 2008-03-02 .
  8. Olson. L.. Soto. A. M.. Knoop. F. C.. Conlon. J. M.. 2001-11-09. Pseudin-2: an antimicrobial peptide with low hemolytic activity from the skin of the paradoxical frog. Biochemical and Biophysical Research Communications. 288. 4. 1001–1005. 10.1006/bbrc.2001.5884. 0006-291X. 11689009.
  9. Jeon. Dasom. Jeong. Min-Cheol. Jacob. Binu. Bang. Jeong Kyu. Kim. Eun-Hee. Cheong. Chaejoon. Jung. In Duk. Park. Yoonkyung. Kim. Yangmee. 2017-05-03. Investigation of cationicity and structure of pseudin-2 analogues for enhanced bacterial selectivity and anti-inflammatory activity. Scientific Reports. en. 7. 1. 1455. 10.1038/s41598-017-01474-0. 28469145. 5431190. 2017NatSR...7.1455J. 2045-2322. free.
  10. Conlon. J. Michael. 2011-07-11. Structural diversity and species distribution of host-defense peptides in frog skin secretions. Cellular and Molecular Life Sciences. 68. 13. 2303–2315. 10.1007/s00018-011-0720-8. 1420-9071. 21560068. 24189013 . 11114843.

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